The modifications are necessary to stabilise the left abutment under certain static and seismic loading conditions. The Modification Report for Deadwood dam was approved by the US Congress earlier this month when a 30-day waiting period expired clearing the way for the award. The contractor has until the end of October 2003 to complete the work.

The modifications to the dam are authorised under the Reclamation Safety of Dams Act of 1978, as amended in 1984. According to the Act, authorised purposes are required to repay 15% of the safety of dam’s project costs. Irrigation and power are the authorised purposes of Deadwood dam. The total project cost, including the construction contract, design costs, construction management, investigations, and other Safety of Dams activities is estimated at about US$3M.

Deadwood dam was completed by USBR in 1931. The 50.3m high, concrete arch dam can store 199Mm3 of water, of which Emmett Irrigation District owns 90% of the contracted space. Water released from Deadwood dam is also used for power generation at Black Canyon dam and other facilities further downstream.